Numerical Investigation of Distribution Laws of Shear Force in Box Girder Webs

Abstract

To study the shear force distribution laws of a box girder with a single-box multichamber (SB-MC) configuration for different supporting conditions, numbers of webs, stiffness of end diaphragm, and web thickness values, a box girder with SB-MC was numerically simulated using three-dimensional finite element model. According to the comparison results of web shear force, the concept of η, a shear-increased coefficient for webs, was introduced. The results show that supporting conditions and chambers have a significant impact on the shear-increased coefficient η, and end diaphragm must be set up in the 3D finite element model when calculating η. Nonlinear analysis shows that in the elastic phase, the shear-increased coefficient η basically does not change, but in the cracking stage, the coefficient η of each web changes with the degree of web cracking, and side-webs (S-Webs) reach the ultimate load first. The variation of the web thickness hardly affects the distribution of the shear force, so the method to adjust the web thickness of S-Web was proposed according to the result of shear-increased coefficient η to improve the shear resistance of the box girder.

Numerical Analysis of Dead Load Shear Force Distribution in Webs of Multicell Inclined Web Box‐Girder Bridge

“…Xue [10] showed that support condition and cell number significantly affect the distribution of web shear forces. In this study, the outermost web is rotated along the centre of the web by 10°, 15°, 20°, and 25°, respectively, as shown in Figure 1(b).…”

“…For the compression and tension of concrete, a parabolic compression model and a linear softening tension model [10,12] of the total strain crack model are used, respectively. e strength grade of the concrete is C40.…”

“…To a large extent, researchers and designers believe that the dead load is evenly distributed between the different webs of a multicell girder. Xue [10] studied the shear force distribution caused by dead load and found that the support condition and cell number of the box have a significant impact on the shear distribution between the webs of multicell girders, and the variation in the web thickness has little effect on the distribution. Under certain circumstances, the shear force carried by the outermost web is 1.65 times the average shear force, which indicates that the difference in the shear force distribution caused by dead load in each web cannot be neglected.…”

“…In this study, the webs are analysed according to different web slopes, cell numbers, and support conditions. e total stress-strain model, which has many practical applications [10,11] in analysing concrete structures, uses nonlinear three-dimensional finite element analysis to study the shear redistribution of cracked webs. .…”

Steel Fibre Reinforced Concrete Meso‐Scale Numerical Analysis

“…e total strain crack model has many satisfactory examples in analysing concrete structures [37,38]. e parabolic model of the total strain crack model is a commonly used model for the constitutive relationship of concrete under compression.…”